P15DF?

chzzel · 08-05-2015, 11:42 PM

Hey guys!

So my car has been acting up lately. Rough idle on cold start followed by limp mode, as well as the car hesitating or stumbling on acceleration (almost like a fuel cut). All seems to be fine after a quick restart...but it's getting kind of old. About 3 weeks ago, I had my n55 335i in for service at Serpa BMW to get this issue diagnosed. At first, they couldn't replicate the issue - but after some time, they "determined" it was a coil that was malfunctioning. Long story short, they replaced all 6 coils. They called me after having my car for a week and told me that the issue was resolved. The day I picked the car up, it was still doing the same stupid hesitating/stumbling on acceleration and the mechanic said that there were no fault codes. It ended up throwing a code a few days later and I used my OBD2 code reader to pull the code. It threw a P15DF...not exactly sure what it means.

I'm leaning towards the HPFP at this time. Anyone have similar problems? Same code being thrown? All suggestions welcome!

chzzel · 08-08-2015, 10:50 PM

bump!

lakeman · 07-03-2016, 10:00 AM

Hi, my n55, 2011 X5 doing the same thing, and throwing the same code. Did you ever resolve your issues with yours? HPFP? I'm getting other codes also: P0087, P2421. Check engine light and limp mode about every other day, especially in 95 degree heat. I reset and the car runs great for a day or two. Sure appreciate any info. Thanks.

BTW: I've had all of the Vanos issues. Broken bolts, into the engine. Timing chain, crankshaft etc etc etc. all repaired by Dealer, but took months for them to complete. All part of the N55 saga.

haashim.is · 07-17-2023, 02:57 AM

Let the car idle for a little while before turning it off!!!!!

I've had similar issues with the annoying long cranks followed by a rough idle and then limp mode with hpfp codes. I replaced the hpfp (110k miles probably needed to be replaced regardless) and the car seemed to be running better, but the annoying horrible starts and limp mode would come back. I read sooooo many threads about the issue and everyone says stuff about fueling issues faulty hpfp, injectors, etc. I had already done spark plugs and coils and now hpfp, and I already had index 12 injectors so i was not about to drop another 3k for injectors (index 12s price crazyyyy). Believe it or not in a tik tok I saw after pushing a car let it idle for about 20-30 secs at least so oil can circulate throughout the system (especially the turbos) and it actually worked. I tested it by pushing the car to its limits with antilag, launch controls, etc. then letting it idle for a little while (less than a min is plenty but at least 30 secs). Havent had that annoying limp mode or that scary idle that sounds like the engine is saying a knock knock joke to me

. Anyways i hope this helps and goodluck to anyone dealing with this problem, be careful about just throwing new parts and money at the car because it may not resolve anything.

anjuna · 07-21-2023, 09:54 AM

^meh

chzzel - are you tuned? setting too high of a rail pressure at idle or low load has caused my fueling system to pitch a fit.

I can remedy the issue very quickly by pulling the fueling relay in the back and putting it back in.

08-05-2015, 11:42 PM	#1
chzzel New Member 1 Rep 7 Posts Drives: 2011 BMW 335i xDrive 6MT Join Date: Oct 2014 Location: Stouffville, Ontario iTrader: (0)	P15DF? Hey guys! So my car has been acting up lately. Rough idle on cold start followed by limp mode, as well as the car hesitating or stumbling on acceleration (almost like a fuel cut). All seems to be fine after a quick restart...but it's getting kind of old. About 3 weeks ago, I had my n55 335i in for service at Serpa BMW to get this issue diagnosed. At first, they couldn't replicate the issue - but after some time, they "determined" it was a coil that was malfunctioning. Long story short, they replaced all 6 coils. They called me after having my car for a week and told me that the issue was resolved. The day I picked the car up, it was still doing the same stupid hesitating/stumbling on acceleration and the mechanic said that there were no fault codes. It ended up throwing a code a few days later and I used my OBD2 code reader to pull the code. It threw a P15DF...not exactly sure what it means. I'm leaning towards the HPFP at this time. Anyone have similar problems? Same code being thrown? All suggestions welcome!
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08-08-2015, 10:50 PM	#2
chzzel New Member 1 Rep 7 Posts Drives: 2011 BMW 335i xDrive 6MT Join Date: Oct 2014 Location: Stouffville, Ontario iTrader: (0)	bump!
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07-03-2016, 10:00 AM	#3
lakeman New Member 0 Rep 9 Posts Drives: 2011 X5 E70 N55 Join Date: Apr 2014 Location: Gainesville, Ga, USA iTrader: (0)	P15DF Code Hi, my n55, 2011 X5 doing the same thing, and throwing the same code. Did you ever resolve your issues with yours? HPFP? I'm getting other codes also: P0087, P2421. Check engine light and limp mode about every other day, especially in 95 degree heat. I reset and the car runs great for a day or two. Sure appreciate any info. Thanks. BTW: I've had all of the Vanos issues. Broken bolts, into the engine. Timing chain, crankshaft etc etc etc. all repaired by Dealer, but took months for them to complete. All part of the N55 saga.
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07-17-2023, 02:57 AM	#4
haashim.is Registered 0 Rep 1 Posts Drives: 2011 BMW 335is DCT Join Date: Apr 2023 Location: CA iTrader: (0) Garage List 2011 BMW 335is [0.00] 2011 BMW 335is [0.00]	Possible solution EASY Let the car idle for a little while before turning it off!!!!! I've had similar issues with the annoying long cranks followed by a rough idle and then limp mode with hpfp codes. I replaced the hpfp (110k miles probably needed to be replaced regardless) and the car seemed to be running better, but the annoying horrible starts and limp mode would come back. I read sooooo many threads about the issue and everyone says stuff about fueling issues faulty hpfp, injectors, etc. I had already done spark plugs and coils and now hpfp, and I already had index 12 injectors so i was not about to drop another 3k for injectors (index 12s price crazyyyy). Believe it or not in a tik tok I saw after pushing a car let it idle for about 20-30 secs at least so oil can circulate throughout the system (especially the turbos) and it actually worked. I tested it by pushing the car to its limits with antilag, launch controls, etc. then letting it idle for a little while (less than a min is plenty but at least 30 secs). Havent had that annoying limp mode or that scary idle that sounds like the engine is saying a knock knock joke to me . Anyways i hope this helps and goodluck to anyone dealing with this problem, be careful about just throwing new parts and money at the car because it may not resolve anything.
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07-21-2023, 09:54 AM	#5
anjuna First Lieutenant 307 Rep 394 Posts Drives: f25 Join Date: Feb 2017 Location: houston iTrader: (0)	^meh chzzel - are you tuned? setting too high of a rail pressure at idle or low load has caused my fueling system to pitch a fit. I can remedy the issue very quickly by pulling the fueling relay in the back and putting it back in.
	Appreciate 0 Quote